We've never used beef backbone, but I have some pork backbone cooking right now-- if it helps, pork backbone tastes very much like ribs, so I'm guessing that beef backbone may taste like beef ribs and behave in the same way? We just put bbq sauce on ours.
I guess I think that bones are bones, they all have marrow, right, so if you cook them long enough, you should get the minerals out of them. OP, if you do use them, please post back with how your stock turns out.
Follow Mothering